It is known to provide a refrigerator operated by a gas burner for use in house trailers, boats, and the like. The conduits supplying combustion air to the gas burner and fresh air to the space or room in which the apparatus is mounted, as well as the conduits leading the combustion gases away from the gas burner, are of different design. Since the combustion gases can be injurious to people present in the room in which the apparatus is mounted and since the burner flame involves risk of fire in the event there are combustible gases in the room, strong efforts have been made in prior construction to provide a sealed combustion system. In such a known system, the combustion air, which is led from the ambient to the gas burner, as well as the combustion gases, are conveyed through a system of conduits. This system communicates only with the air outside the room and is nowhere in communication with the atmosphere present in the room.
A number of sealed combustion systems have already been produced and are on the market, but the known constructions are not fully satisfactory with regard to operational safety. Both house trailers and boats are subject to strong winds and/or comparatively strong air gusts occurring in different directions, and hence the pressure conditions in a sealed combustion system can change in such a manner that the flow of air and combustion gas occasionally ceases and the flame goes out due to lack of oxygen. Theoretically, this occurrence could be remedied in two ways: either by providing automatic re-lighting when the flame has extinguished, or by forming the sealed system and its connection to ambient air in such a way that changes of the pressure conditions outside the space or room cannot affect the flow through the sealed combustion system to such an extent that the burner flame is extinguished.
The known ventilators for the previously described apparatus which are now available are improvements compared with what was obtainable earlier. However, they are not entirely windproof. A prime difficulty in preventing a break in the operation of a gas burner in a sealed combustion system depends on the fact that air gusts occur in different directions and that the force of the wind may vary considerably. Therefore, a ventilator of this type cannot have a protecting device which is asymmetric. Furthermore, it must not be possible for the combustion gases dischaged from the system to be blown or led into the air intake so that the burner will get an inappropriate or insufficient quantity of air for combustion purposes. Furthermore, it is not desired that the combustion gases pass through the combustion gas conduit back to the burner, which in such a case would not receive any air for the combustion and its flame would thus be extinguished.
It is an object of the present invention to provide a sealed combustion system for the gas burner of a refrigerator, or the like, with a construction and arrangement whereby the intermittent operation of the burner is overcome due to the changing pressure conditions of the atmospheric air surrounding the ends of the combustion gas conduit and the air intake conduits adjacent to the ambient .